Usefulness of BioFire FilmArray BCID2 for Blood Culture Processing in Clinical Practice

Abstract

Rapid pathogen characterization from positive blood cultures (BC) can improve management of patients with blood stream infections (BSI). The FilmArray blood culture identification (BCID) assay is a molecular test approved for direct identification of BSI causing pathogens from positive BC. A recently updated version of the panel (BCID2) comprises improved species identification characteristics, and allows for the detection of one ESBL- and several carbapenemase-encoding genes. Here, the clinical performance of the BCID2 assay for species identification in 180 positive BCs was evaluated. BCID2 results were concordant with standard of care (SOC) in 159/180 (88.3%) BCs. 68/74 (91.9%) and 71/74 (96.0%) of all samples growing mono-bacterial, Gram-positive or Gram-negative pathogens, respectively, were identified in agreement with SOC results. Non-concordance was related to the detection of additional pathogens by the BCID2 (n= 4), discrepant species identification (n= 4), or failure of BCID2 to detect on-panel pathogens (n= 1). A number (12/31; 38.7%) of discordant results became evident in poly-microbial BC specimens. BCID2 identified presence of blaCTX-M carrying species in 12 BC specimens, but failed to predict a third-generation cephalosporin resistance in four isolates exhibiting independent cephalosporin-resistance mechanisms. Carbapenem-resistance related to the presence of blaVIM-2 or blaOxa-48-like was correctly predicted in two isolates. In conclusion, BCID2 assay is a reliable tool for rapid BC processing and species identification. Despite inclusion of common ESBL- or carbapenemase-encoding markers, the multifactorial nature of β–lactam resistance in Gram-negative organisms warrants combination of BCID2 with (rapid) phenotypic susceptibility assays.

Performance of the BioFire Blood Culture Identification 2 panel for the diagnosis of bloodstream infections

“…Agreement between BCID2 and traditional culture methods was high in our study, with an overall concordance for on-panel pathogens on monomicrobial blood cultures of 98%, in line with existing reports [10,11,13,16,17]. This is a promising concordance rate, although it should be acknowledged that not all BCID2 targets were detected in our samples, therefore their performance could not be evaluated.…”

“…Concordance between conventional testing and BCID2 for polymicrobial blood cultures is reported to be lower than that for monomicrobial blood cultures by some of the available performance studies [10,11]. Specifically, Berinson et al reported a concordance rate for polymicrobial samples of 61.3% [10] while Sparks et al of 28.6%, although in the latter study most disagreement was due to the culture-based identification of BCID2 off-panel pathogens, and possibly affected by a laboratory contamination [11].…”

“…A new version of this assay has been recently released (BioFire Blood Culture Identification 2 Panel, bioMerieux, France) resulting in a broader panel including 33 pathogens (26 bacterial genera/species and 7 fungal species) and 10 resistance markers; few studies have evaluated the performance of BCID2 on clinical samples so far [10,11,12,13,14].…”

A Multicenter Clinical Study To Demonstrate the Diagnostic Accuracy of the GenMark Dx ePlex Blood Culture Identification Gram-Negative Panel

“…Currently, there are several commercially available, FDA-cleared blood culture identification (BCID) systems that use molecular methods for rapid identification of pathogens and antibiotic resistance genes (ARGs) in positive blood culture (PBC) bottles. One such system offers a single panel to detect 43 Gram-positive (GP) and Gram-negative (GN) bacteria and yeasts as well as 10 antibiotic resistance markers ( 5 – 7 ). Two other platforms offer separate panels for the identification of GP and GN bacteria, but neither has a fungal panel ( 8 , 9 ).…”

Recent Advances in the Use of Molecular Methods for the Diagnosis of Bacterial Infections

“…The FilmArray Blood Culture Identification panel detects 33 pathogen and 10 antimicrobial resistance genes associated with bloodstream infections [56]. For patients with sepsis, a leading cause of death in hospital patients, rapid identification of the organism from blood cultures in combination with the indication of pathogen-associated resistance genes is critical for reducing patient morbidity and mortality [57]. In addition, according to international guidelines for the management of sepsis, in order to reduce the occurrence of antimicrobial resistance, it is important to replace broad-spectrum therapy with appropriate antibiotic therapy as soon as pathogens are identified [58].…”